We shouldn't rejoin just because it would be good for growth. We should rejoin because we have shared goals and values. The growth is a welcome side-effect.
...but we need to keep a sovereign currency. We're going to need it to get out of the hole we're in. We're going to have to increase spending drastically and the ECB would never allow that.
Freedom of movement was a good thing, and immigration has become far more uncontrolled since.